In July 1970 EMI opened their own cassette duplication facilities at their manufacturing plant in Hayes, at which point EMI cassette and 8-track issuing really began in earnest, embarking on a huge programme releasing back catalogue on tape.
In order to justify the increasing expenditure EMI were investing in tape duplication, it became necessary to show a concerted marketing effort was in place by utilising precious inlay space to plug other titles.
Many late 1960s EMI vinyl LPs also contained similar sections at the foot of the LP sleeve back covers.
The catalogue numbers were moved to the inlay reverse at this point (see below).
Up until around 1971, the back covers of vinyl LPs were created using 'letterpress' techniques, wherein moveable type (pre-cast metal blocks containing the shapes of letterforms, logos and graphic elements like lines, bullets and curves) had to be arranged in a rack to create a printing plate. Usual practice was to make a sub-mould with all the type (and logos and graphic elements) in place, to produce a single stamper which could apply the back cover graphics in one operation and with no risk of individual letters or logos falling out. Any photographs that needed to appear would have to be made into a physical plate using the 'halftone' process in which the images would be converted to a pattern of dots, which could thence be converted into peaks and troughs etched into the surface of the plate. This normally would be black-and-white only. This process was extended to the production of early cassette inlays, with the added complication of having to create halftone plates of the four colours that make up the colour illustration of the album cover. This would be a photomechanical process that would result in four stampers each containing a fine pattern of dots representing areas of the four printing process colours, cyan (light blue), magenta (dark pink), yellow and black. Halftone separations of this era would tend to be fairly low resolution, having what would be termed a low 'screen frequency'. This would be necessary in order to prevent blobbing of the inks or trying to prints dots so fine the ink wouldn't grip the paper during pressing.
If you ever got hold of an EMI tape like the 'Easy Rider' example here, you will be able to hold the inlay up to the light and see the indentations in the paper left by the letterpress - i.e. all the lettering creates a visible 'crater' in the surface.
The reverse of the inlays continued to be used for the tracklistings, still for a while headed 'Track 1' and 'Track 2'. UK and international (1E) catalogue numbers were moved to this section in 1970. Totally superfluous 'matrix numbers' were even allocated to each side (on this example 'T-SSL 5018A' and 'B'). These really meant nothing, because with cassettes both sides are duplicated at once from a single master tape, containing Sides A and B in parallel (in exactly the same arrangement as on the finished cassettes themselves).
Nearly all EMI tapes featured the black box 'EMI' logo introduced by the company in late 1967 plus a second black box 'label' logo underneath (right) - either Parlophone, Columbia, HMV, Stateside, Tamla Motown or Harvest. However sometimes earlier versions of the logos were used (including the earlier 'oval world' EMI logo), and on occasions no logo at all would be present - which could possibly be put down to a lack of sufficient quantities of letterpress blocks for the graphics. Remember that for as many copies of these as were required, they would have to be recast as a piece of metalwork, with of course an associated cost involved.
Two ways of identifying where each cassette fitted in EMI's release schedule can be found on inlays of this period. In late 1968, EMI had introduced an international catalogue numbering system which sat alongside the 'traditional' catalogue numbers used in the UK. In Beatles For Sale (above) for example, the UK catalogue number is
TC-PCS 3062 (being the catalogue number used for the original vinyl, with the prefix 'TC-' for 'Tape Cassette') and the international catalogue number is 1E 262 04200 (the 'o' in the middle was actually meant to be a bullet).
A full breakdown of how this numbering system worked can be found by clicking here. In short however, all EMI releases from the UK started with Deep Purple's The Book Of Taliesyn with 1E ... 04000 in 1969, so Beatles For Sale was the 201st title registered with this system. Ironically, Yellow Submarine received the number 1E ... 04002 simply because the time of its original vinyl release came shortly after this system was introduced - but the actual cassette release didn't happen until 1974!
Date codes were introduced in July 1970 to co-incide with the opening of EMI's own cassette duplication facilities at its Hayes factory. The date of first issue can be gleaned via the four digits shown in the bottom-right - 7010 EJD in this example. This means '1970 October', and the letters 'EJD' stand for 'Ernest J. Day', the company which printed the inlay. EMI used three printing firms in those days - EJD, G&L (Garrod & Lofthouse) and DP (Data Packaging Corporation).
The advertising space was made 'genre-specific', as can been seen from this Deep Purple example - from the days when the phrase "Heavy Metal" hadn't quite entered popular lexicon. Purple's Concerto perhaps didn't belong quite in that category though.
Interestingly, the vinyl album starts with "Speed King" and indeed although it appears here on tape at the start of 'Track 2', the so-called matrix number shown is T-SHVL 777A, whereas the 'Track 1' matrix number is T-SHVL 777B, perhaps indicating that the sides were originally intended to be juxtaposed.